Device for feeding acoustic films at constant speed



Aug. 31, 1926. 1,597,819

A. POULSEN ET AL DEVICE FOR FEEDING ACOUSTIC FILMS AT CONSTANT SPEED Filed July 9, 1924 ArnoZcZ PwZsen AxeZ CarZ Georg Pete/wen ATTORNEY Pasta A... 31. 1926. 1,597,819 UNITED STATES-PATENT orrlce.

ARNOLD POULSEN AND AXEL CARL GEORG PETERSEN, OF COPENHAGEN, DENMARK.

DEVICE FOR FEEDING ACOUSTIC FILMS AT CONSTANT SPEED.

Application filed July 9, 1924. Serial No. 725,070.

For regulation of the speed at which film Figs. 3 and 4 show, in diagrammatic sideis fed forward in cinematographic apparaelevation, a feeding device according to Fig. tuses and the like, it has been proposed be- 1 combined with sound-recording and reprofore, as is well known, to use a flywheel ducing apparatus, respectively. 60 i 6 which drives a roller on which the film is Referring to the drawing, 1 is a film passrunning. ing around a roller 2 having a rough 'sur- One condition which is necessary in order face, the film being moved, in the direction ,that a constant speedof motion of the film indicated by the arrow P in Fig. 1, by a by means of aregulatin mechanism of such driving mechanism which is here shown as 65 10 nature may be attaine independently of comprising a film feeding wheel 3 of known smaller variations of speed in the mechakind! The feeding wheel 3 is driven for innism serving to operate the film, is that the stance by an electromo'tor 3' (Fig. l) in such film be prevented fromsliding on the said a manner that it moves at ap roximately roller, and that the mass of the flywheel be uniform speed. Owing to the friction so large that the flywheel, during temporary against the surface of the roller 2, the film smaller variations of the driving power, may 1 will rotate the latter and, thereby, drive a maintain the s eed of motion of all the roflywheel 4 connected to the roller and; servtary parts of t e apparatus, and retard the ing in known manner to maintain the rotary driving mechanism, when the latter tends speed of theroller 2 uniform. to run at higher s eed, In order to prevent the film from" sliding The object of t e present invention is to on the roller 2, the former'is pressed against provide film-feeding mechanism by which the surface-of the roller by means of rubber the said condition'is satisfied. For this purcovered rolls 5 which are controlledby a pose, the flywheel and the roller coupled spring or springs 7, each of the said rolls thereto are driven by. the film, and means running partly on the surface of the roller are provided which engage the leading porand partly on the film 1, Fig. 2, Where thetion of the filmi. e., the ortion of the film rolls 5 for the sake. of clearness are shown located between the filmeedin roller and lifted somewhat up from the'film. The the roller cou led to the flywhee and exert rolls' 5 are journalled at the ends of pivoted thereon a resi 'ent pressure which causes the arms 6 to which the spring or springs 7 filmto pass in a bight between said two are attached. rollers. .The extent of the bight increases The portion of the film 1 which is located and decreases automatically with the variabetween the roller 2 and the feeding wheel tion of the speed of the feeding roller and 3 passes in a bight over a roller 8, which is 35 its rotating means, and will thereby prevent journalled on the end of a pivoted arm 9 slight temporary variations of the speed of actuated by a spring 11, in such, a manner the latter from being transmitted to the that the .roller 8 exerts a resilient pressure on portion of the film passing-the'sound-record; the film. mg or sound-reproducin point. Besides, When for some reason or other the rotary said bight has the efiectt at sudden or perspeed of the feeding wheel 3 is temporarily manent variations of the speed of the driv-- increased, the consequence will be that more ing motor are only gradually "transmitted fil'in per second must run to the feeding to the flywheel and to the arriving portion of wheel 3 than before, whereby thelength of I the film, so that the tension in the latter will the said bight will be reduced, and the arm 45 nowhere, be exposed to any corresponding 9 with the roller 8 willthen swing out in the sudden increase,but will increase gradually, direction indicated' by the arrow p in Figure and rupture of the film will be prevented. 1. The increased supply of'film to the feed- The further details of the invention will ing; wheel 3 due to the increase of speed will the same illustrated in the accompanying only temporarily, be effected by a shortening drawing, I i 7 of the said bight, without any appreciable Fig. 1 showing, diagrammatically in side variation of the tensile stress of the film.

elevation, a feeding and regulating. mecha If the speed of the feeding wheel 3 is re nism, and,

Fig. 2 a detail of the same,'on a larger swim in such a manner that the length'of scale in treat ele ator. v the 5m bight will be in rea d c re p nd:

become apparent .from the construction of 'therefore, ifthe increase of speed occurs duced,'the arm 9 with the roller '8 will 1 ing to the decreased supply of film to the feeding wheel. When the speed of the feeding wheel 3 once more becomes normal, then the arm 9 will gradually swing back into the position shown in Fi re 1, the bight being gradually shortene down again to its normal length. By suitable selection of the size of the flywheel 4, the result will be attained that this flywheel maintains the speed of motion of the film practically constant during. the time passing from the occurrence of a speed reduction of a certain duration, until the film bight is again reduced to its normal length. By giving the bight of film a suitable size, the result may be attained that. all variations of the speed of the driving mechanism, within certain limits which may be presumed not to be exceeded during normal conditions, will be entirely equalized in the manner here described.

In case of a sudden great increase or a permanent increase ofthe speed of the driving mechanism, the bight of film'will be shortened considerably, and the arm 9 with the roller 8 will move considerably in the direction indicated by the arrow p. Thereby, however, the pressure ofthe roller 8 against the film will be increased gradually by the spring 11 and, consequently, the said spring will offer a 1gradually increasing reslstance againsts ortening of the film bight. In consequence, the tension of the 'film-bight and, hence, the tensile stress in the portion of "the film between the roller 2 and the feeding wheel 3will gradually become greater, and will gradually increase the speed of the flywheel, until there has been established a new state of equilibrium between the driving power and the resistance a ainst motion-of,the rotary parts correspon 'ng to the new speed at which the drivi mechanism adjusts itself.

Sud en and permanent increases of speed are in this manner transmitted quite grad ually to the flywheel and to the portion of the film running towards the roller 2, without suchspeed increments causing any sudden and impermissible increases of the tension of the film.

The size of the flywheel 4 is independent of the mass and motive energy of the other rotary parts, and it depends, aside from the frictional resistances occurring in the sound record gate 10 concerned and in the bearings of the rotary parts, and from the increase of tension of the spring 7 caused by a certain rotation in the direction p, only upon the duration of the speed variations to be equalized, the mass of the flywheel having to be selected in such a manner that the flywheel, within the time interval in which a speed variation to be compensated may occur, must be able to maintain the speed of the roller 2 practically constant.

- Instead of a roller 8 use may be made of a loop,arm or other suitable member resting resiliently against the film and doing the same service as the roller 8.

In the apparatus illustrated in Figs. 3 and 4, the film 1 is moved by the feeding roller 3, which is an ordinary pin-roller, and by a second pin-roller 20 coupled in any suitable manner to the pin-roller 3 or to the driving mechanism in order that the two rollers20 and 3 may rotate synchronously. 25 in Fig. 4 indicates guide rollers for the film.

According to Fig. 3, sound waves are graphically recorded on the film l by means of an oscillating mirror 30, which is sup ported by a wire loop 31 and is caused to oscillate in known manner in conformity with the phonic currents that pass through the said loop due to the action of an electromagnet 32 which is energized from a current source 33. 34 indicates a beam of light reflected by the mirror 30 towards a lens 36, which concentrates the said lighten the film, thus causing in known manner the recording of the sounds on the film. The light 34 is produced by a light source (not shown) arranged in suitable manner in the chamber 35 of the apparatus.

-According to Fig. 4, the sound waves recorded on the film 1 are reproduced in known manner by illuminating the film from a light source 40, a condensing lens 41 being inserted between the said light source and the film. By means of a lens 42, an image of the recorded aphic representations is formed across a ight-sensitive cell 43, for instance a selenium,cell, inserted in a reproducing circuit 44.

Having now particularly descrlbed and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we claim is 1. A constant-speed film-feeding mechanism, comprising a'feeding roller; means for continuously rotating the same; a flywheel; a roller coupled to the flywheel and driven by the passage of the film thereover; and means to compensate variations in the motion of the film due. to irregularities in the rotary motion of the feedin roller.

2. A constant-speed filmceding mechanism, comprising a feeding roller; means for continuously rotating the same; a flywheel; a roller coupled to theflywheel and driven by friction action of the film passing thereover; and means to compensate variations in the motion of the film due to irre larities in the rotary motion of the ceding 7 3. .A constant-speed film-feeding mechanism comprising a feeding roller; means for continuously rotatinglthe same; a flywheel; a roller coupled to t e flywheel and driven by friction action of the film passing thereroller.

pressure WhlCh causesthe film to pass in "a Leonora over; a pivoted lever; 'a roller journalled on one endthereof; and aspring acting to P force 'the-last-n'a'med roller against the r tion of thefilm located between the fee ing'. roller and the flywheel roller with a resilient pressure which causes the film to pass in a ight in its travel from the flywheel roller onward to the feeding roller, the extent of ight over said member in itstravel from the flywheel roller onward to the feeding roller, the extent ofthebight increasing and decreasing in acoordance with the variationsin the speed of the feed roller and its rotating means. k p

5. A constant-speed film-feeding mecha-; nism, comprising a feedin roller; means 1 for continuously rotating t e same; a flywheel; a roller coupled to the fl wheel and driven by friction action of the passing 'thereover; and an ad'ustable member em-o bodying a lever, a 1'0 er journalled on one I natures.

end thereof, and means actingto force the last-namedroller against the portion of the film located between the feeding roller'and the flywheel roller with a resilient ressure which causes the film to pass in a ight in its travel from the flywheel roller onward to .the feeding roller, the extent of the bight increasing and decreasing in accordance with the variations in the speed of the feed roller and itsrotating means. I

6. A constant-speed film-feeding mechanism, comprising a feedin roller; means for continuouslyrotating t e same; a fly- 7 wheel; a roller coupled to said flywheel and.

driven by friction action of the film passing thereover; a pivoted lever; a roller journalledon'one end of said lever; a spring acting upon the lever to force the last named roller against the film and thus cause the .latter to pass in a, bi'ght from the driven roller onward to the driving roller; two

rubber-covered rollers partly overlying the film and part1 overlying the-driven roller; and means a apted to force said rubbercovered rollers against said driven roller and film, so as to secure between the film and the driven roller 'aconsiderable friction effect which prevents the 'filmfrom sliding onthe driven roller.

In testimony whereof they afiix their sig- Aaron) rou sra a AXEL cam. cacao airman.- 

